Music selection and organization using audio fingerprints

ABSTRACT

A content selection system and method for identifying and organizing moods in content using objectively measured scores for rhythm, texture and pitch (RTP) and clustered into six mood classifications based on an objective analysis of the measured scores. Digitized representations of the content may also be identified and organized based on the content&#39;s frequency data, three-dimensional shapes derived from the digitized representations, and colors derived from the frequency data. Each piece of content may be identified by at least a mood shape, but may also be identified by a mood color and/or a mood based on the clustered RTP scores and/or the digitized representation. Users of the selection system may be able to view the moods identified in the different manners, or combinations of two or three mood identifying manners and select and organize content based on the identified moods.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 14/671,973, filed Mar. 27, 2015, which is acontinuation-in-part of U.S. patent application Ser. No. 14/603,324,filed Jan. 22, 2015; and is a continuation-in-part of U.S. patentapplication Ser. No. 14/603,325, filed Jan. 22, 2015; both of which area continuation-in-part of U.S. patent application Ser. No. 13/828,656,filed Mar. 14, 2013, now U.S. Pat. No. 9,639,871, the entire contents ofeach of which are incorporated herein by reference.

U.S. patent application Ser. Nos. 14/603,324 and 14/603,325 both claimbenefit under 35 U.S.C. § 119(e) of Provisional U.S. Patent ApplicationNo. 61/930,442, filed Jan. 22, 2014, and of Provisional U.S. PatentApplication No. 61/930,444, filed Jan. 22, 2014, the entire contents ofeach of which are incorporated herein by reference.

U.S. patent application Ser. No. 14/671,973 also claims benefit under 35U.S.C. § 119(e) of Provisional Application No. 61/971,490, filed Mar.27, 2014, the entire contents of which are incorporated herein byreference.

This application is also a continuation-in-part of U.S. patentapplication Ser. No. 14/671,979, filed Mar. 27, 2015, the entirecontents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to content selection and organizationsystems.

BACKGROUND

Individual pieces of music are identified herein as “songs” forsimplicity, regardless of whether such songs actually involve any formof human singing. Rather, a song is an individual piece of music thathas a beginning and an end, regardless of its length, the type of musicbeing played therein, whether it is instrumental, vocal or a combinationof both, and regardless of whether it is part of a collection of songs,such as an album, or by itself, a single.

Traditional content selection systems, especially music selectionssystems, such as APPLE ITUNES, tend to rely on content types based onstyle, genre, content author(s), content performer(s), etc., forenabling users to browse through vast libraries of content and makeselections to watch, listen, rent, buy, etc. For example, in such musicselection systems, the music is often organized by the genre, style ortype of music, i.e., jazz, classical, hip hop, rock and roll,electronic, etc., and within such genres, the music may be furtherclassified by the artist, author, record label, era (i.e., 50's rock),etc.

Some music selection systems will also make recommendations for musicbased on user preferences and other factors. Pandora Media, Inc.'sPANDORA radio system, for example, allows users to pick music based ongenre and artists, and will then recommend additional songs the user maybe interested in listening to based on the user's own identificationsystem. This identification system is derived from the Music GenomeProject. While the details of the Music Genome Project do not appear tobe publicly available, certain unverified information about it isavailable on-line. For example, Wikipedia states that the Music GenomeProject uses over 450 different musical attributes, combined into largergroups called focus traits, to make these recommendations. There arealleged to be thousands of focus traits, including rhythm syncopation,key tonality, vocal harmonies, and displayed instrumental proficiency.See, http://en.wikipedia.org/wiki/Music_Genome_Project.

According to Wikipedia [[cite]], in accordance with the Music GenomeProject, each song is represented by a vector (a list of attributes)containing up to 450 or more attributes or “genes,” as noted above. Eachgene corresponds to a characteristic of the music, for example, genderof lead vocalist, level of distortion on the electric guitar, type ofbackground vocals, etc. Different genres of music will typically havedifferent sets of genes, e.g., 150 genes for some types of music, 350 to400 genes for other types, and as many as 450 genes for some forms ofclassical music. Each gene is assigned a number between 0 and 5, inhalf-integer increments. The assignment is performed by a human in aprocess that takes 20 to 30 minutes per song. Some percentage of thesongs is further analyzed by other humans to ensure conformity. Distancefunctions are used to develop lists of songs related to a selected songbased on the vector assigned to the selected song.

While the Music Genome Project represents an ambitious and detailedidentification system, it suffers from many shortcomings as a result ofits inherent complexity. The most significant of these deficiencies isthat it often recommends songs, as implemented by PANDORA, as beingsimilar to other songs, but listeners of those songs are not capable ofidentifying why those songs were determined to be similar. There may bevery good reasons, among the hundreds of attributes being used to makedeterminations of similarities between the songs, but those similaritiesdo not appear to relate to what most listeners hear or feel.Accordingly, a better, more simplistic solution is needed.

Human identification relies on human perception, which is a subjectivesystem. Human perception is believed to be involved because songsidentified by a particular mood and a particular color may or may notsound anything like other songs identified by the same mood and color.This tends to indicate human perception as a subjective error factor inidentifying music in this manner.

SUMMARY

A content selection system and method for identifying and organizingmoods in content using objectively measured scores for rhythm, textureand pitch (RTP) and clustered into six mood classifications based on anobjective analysis of the measured scores. Digitized representations ofthe content may also be identified and organized based on the content'sfrequency data, three-dimensional shapes derived from the digitizedrepresentations, and colors derived from the frequency data. Each pieceof content may be identified by at least a mood shape, but may also beidentified by a mood color and/or a mood based on the clustered RTPscores and/or the digitized representation. In a further embodiment, theRTP-based mood classifications may be used in place of fingerprints andcombined with color and shape. Users of the selection system may be ableto view the moods identified in the different manners, or combinationsof two or three mood identifying manners and select, customize andorganize content based on the identified moods.

BRIEF DESCRIPTION OF THE DRAWINGS

Throughout the drawings, reference numbers may be re-used to indicatecorrespondence between referenced elements. The drawings are provided toillustrate examples described herein and are not intended to limit thescope of the disclosure.

FIG. 1 illustrates an audio file represented as a waveform.

FIG. 2 illustrates an audio file represented as a spectrogram.

FIG. 3 illustrates a visual representation of chroma features in anaudio file.

FIG. 4 illustrates subimage filters for filtering the visualrepresentation of FIG. 3 in order to generate an audio fingerprint.

FIG. 5 illustrates an audio fingerprint.

FIG. 6 illustrates a color wheel associated with a study about howpeople pick different colors to describe different moods.

FIG. 7 illustrates colors associated with moods based on a type of moodring.

FIG. 8 is an illustration of a screenshot capture of images generated byan audio visualizer.

FIG. 9 is an illustration of a three-dimensional shape identifying anaggressive mood.

FIG. 10 is an illustration of a three-dimensional shape identifying asad mood.

FIG. 11 is an illustration of a three-dimensional shape identifying aneutral mood.

FIGS. 12A and 12B are illustrating three-dimensional shapes identifyingdifferent levels of an aggressive mood.

FIG. 13 is an illustration of how moods in content are identified, inaccordance with an embodiment, through a three part classification modelinvolving fingerprint, shape and color.

FIG. 14 is an illustration of rhythm, texture and pitch (RTP) scores fora group of songs used to train the classifying and clustering system.

FIG. 15 is an illustration of classification scores for a larger groupof songs objectively scored by RTP and clustered into one of six moodclasses by the trained classifier.

FIG. 16 is a flow chart illustrating the objective scoring of inputsongs based on RTP, the objective classifying of the scores in order tocluster the songs into different mood classes, various options that maybe performed by a user to customize the mood classes, and the subsequentutilization of the songs by the users as organized in accordance withthis process.

FIG. 17 is a block diagram illustrating a computing system forimplementing the identification, selection, customization andorganization techniques described above.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments of the present disclosure are primarily directed to musicselection and organization, but the principles described herein areequally applicable to other forms of content that involve sound, such asvideo. In particular, embodiments involve a content identification orclassification system that objectively identifies music based on a threepart classification model, an rhythm, texture and pitch (RTP) model, ora combination of both.

The three parts of the three part classification model includefingerprint, color and shape. The generation of the fingerprint will bedescribed first. Music, and songs in particular, may be represented in anumber of different ways that provide a visual representation of themusic. As illustrated in FIG. 1, one of the simplest representations ofmusic, such as a song, is a one dimensional (1-D) waveform thatrepresents changes in the amplitude in the audio file over time.

While such a waveform can be somewhat distinctive of the songrepresented, the amount of information conveyed by the small distortionsin the waveform is limited, making it difficult for someone viewing thewaveform to extract much in the way of perceptual information. If thatsong evoked a mood in someone listening to the song, the 1-D waveformdoes little to represent the characteristics of the song that evoke thatmood.

Accordingly, audio spectrograms based on a short-term Fourier transform,such as represented in FIG. 2, have been developed to provide a morecomplete and precise representation of a song.

The spectrogram is a two dimensional (2-D) representation of frequencyover time, like a waveform, but is considered to provide a more accuraterepresentation of the song because the spectrogram shows changes inintensity on specific frequencies, much like a musical score. The 2-Dspectrogram shows some visual distinction based on signal differencesdue to different audio sources, such as different persons' voices anddifferent types of instruments used to perform the song.

While the spectrogram visually represents some similarities anddifferences in the music, the time-domain signal representation makesthe process of comparing spectrograms using correlation slow andinaccurate. One solution proposed for analyzing the characteristics ofspectrogram images is disclosed by Y. Ke, D. Hoiem, and R. Sukthankar,Computer Vision for Music Identification, In Proceedings of ComputerVision and Pattern Recognition, 2005. In this paper, the authors proposedetermining these characteristics based on: “(a) differences of power inneighboring frequency bands at a particular time; (b) differences ofpower across time within a particular frequency band; (c) shifts indominant frequency over time; (d) peaks of power across frequencies at aparticular time; and (e) peaks of power across time within a particularfrequency band.” Different filters are used to isolate thesecharacteristics from the audio data. If the audio data is formatted in aparticular music format, such as MP3, .WAV, FLAC, etc., the compressedaudio data would first be uncompressed before creating the spectrogramand applying the filters.

One solution for analyzing spectrograms of music in this fashion is theCHROMAPRINT audio fingerprint used by the ACOUSTID database. CHROMAPRINTconverts input audio at a sampling rate of 11025 Hz and a frame size is4096 (0.371 s) with ⅔ overlap. CHROMAPRINT then processes the converteddata by transforming the frequencies into musical notes, represented by12 bins, one for each note, called “chroma features”. FIG. 1, FIG. 2,FIG. 3, FIG. 4, and FIG. 5 and the description herein regardingspectrograms, chromagrams, and audio fingerprints are based onhttps://oxygene.sk/2011/01/how-does-chromaprint-work/. After somefiltering and normalization, an image like that illustrated in FIG. 3may be generated.

While the audio representation, or chromagram, of FIG. 3 is robust andmay be used for other purposes herein, it does not lend itself well tocomparative analysis and needs to be further compacted to be useful inthat regard, which is where the characteristic filters noted above maycome into play. First, the image of FIG. 3 may be scanned from left toright, one pixel at a time, in grayscale, to create a large number ofsubimages. Then, the characteristic filters may be applied to thesubimages to capture intensity differences over time in the musicalnotes represented by the subimages. Each filter may calculate the sum ofspecific areas of the subimages, compare the sums, and arrange the areasin one of six ways, as illustrated in FIG. 4.

The arrangement of filter images from FIG. 4 may be placed over thesubimages, adjusted in size (as long as the filter image fits within thepixel size of the subimage), and the resulting black and white areas maybe processed to derive a single real number representing thearrangement. Every filter may have one or more coefficients associatedwith it that specify the rules for quantizing the real number so thefinal result is an integer between 0 and 3.

CHROMAPRINT uses 16 filters that can each produce an integer that can beencoded into 2 bits. When these are combined, the result is a 32-bitinteger. This same process may be repeated for every subimage generatedfrom the scanned image, resulting in an audio fingerprint, such as thatillustrated in FIG. 5, which can be used to isolate and identify thefrequency characteristics of a song that make that song feel aparticular way to a listener, i.e., identifies the particular mood ormoods of the song.

Audio or acoustic fingerprints may be used to identify audio samples,such as songs, melodies, tunes, advertisements and sound effects. Thismay enable users, for example, to identify the name of a song, theartist(s) that recorded the song, etc., which can then be used tomonitor copyright compliance, licensing compliance, monetizationschemes, etc.

The present disclosure proposes a number of additional novel uses foraudio fingerprints and other components used to generate thefingerprints, including the spectrogram and the chromagram, which may beused to objectively identify texture, pitch and the moods in songs orother content, respectively. When a listener feels a particular emotionas a result of listening to a song (except for any personal connectionto memories or experiences that the listener may also have), thelistener is typically reacting to some inherent quality that can beidentified within the frequencies or other characteristics of the song.Since all aspects of a song may be represented in its frequencies andaspects of those frequencies, and those frequencies are used to generatean audio fingerprint, the mood of that song may therefore also berepresented in that audio fingerprint. By comparing known similaritiesbetween audio fingerprints for songs having the same mood, it may bepossible to identify the mood of a song by simply analyzing the audiofingerprint.

Since some songs represent multiple moods or more or less of a mood thanother songs, the degree of one or more moods represented by a song maybe represented by similarity percentages. For example, if a song is 40%aggressive, 40% sad, and 20% neutral, the mood identifiers may also beassociated with those similarity percentages.

While the use of audio fingerprints to identify moods in a wide range ofsongs is a significant improvement over the existing technique ofrelying on humans to listen to songs in order to identify the mood(s)conveyed by the songs, there is still a causality dilemma. In order toget a classifying/clustering machine to use audio fingerprints toidentify different moods represented in songs, it is first necessary totrain the machine with audio fingerprints that represent different moodsin the songs, which requires humans to listen to some set of songs toidentify the moods in that set so that set can be used to train themachine. As a result, if the machine is not well trained, then the audiofingerprint based identification may not be accurate. This human elementalso reintroduces some of the possible subjective error that exists fromreliance on human-based mood identification.

The present disclosure also addresses these problems by using at leastthree different mood identification techniques to identify each song.While a human element may be used to get the process started, usingmultiple mood identification techniques, such as audio fingerprinting,makes it possible to check each mood identification technique against atleast two other different mood identification techniques, which resultsin better mood identification accuracy.

One additional mood identification technique, as previously noted, isthe use of color. Color is more traditionally thought of in the contextof timbre, which is the term commonly used to describe all of theaspects of a musical sound that have nothing to do with the sound'spitch, loudness or length. For example, two different musicalinstruments playing the same note, at the same loudness and for the samelength of time may still be distinguished from one another because eachof the instruments is generating a complex sound wave containingmultiple different frequencies. Even small differences between thesefrequencies cause the instruments to sound differently and thisdifference is often called the “tone color” or “musical color” of thenote. Words commonly used to identify musical color include clear,reedy, brassy, harsh, warm, resonant, dark, bright, etc., which are notwhat humans tend to think of as visual colors.

Nevertheless, a similar technique may be used to assign visual colors tomusic. The human eye has three kinds of cone cells that sense light withspectral sensitivity peaks in long, middle and middle wavelengths, notedas L, M and S. Visual colors similarly correspond to these wavelengths,with blue in the short wavelength, green in the middle wavelength, andred spanning between the middle wavelength and the long wavelength. Thethree LMS parameters can be represented in three-dimensional space,called “LMS color space” to quantify human color vision. LMS color spacemaps a range of physically produced colors to object descriptions ofcolor as registered in the eye, which are called “tristimulus values.”The tristimulus values describe the way three primary colors can bemixed together to create a given visual color. The same concept may beapplied to music by analogy. In this context, musical tristimulusmeasures the mixture of harmonics in a given sound, grouped into threesections. The first tristimulus may measure the relative weight of thefirst harmonic frequency; the second tristimulus may measure therelative weight of the 2nd, 3rd, and 4th harmonics taken together; andthe third tristimulus may measure the relative weight of all theremaining harmonics. Analyzing musical tristimulus values in a song maymake it possible to assign visual color values to a song.

Since the musical tristimulus values correspond to the frequenciesrepresented in a song, and (as noted above) the frequencies can be usedto identify moods in that song, it follows that the visual colorsidentified in that song can be used to identify the mood(s) of thatsong. However, because songs consist of multiple frequencies, simplevisual color representations of songs tend to end up looking like mixedup rainbows, with the entire visual color spectrum being represented atonce. To address this issue, each visual color representation can befurther analyzed to identify predominant visual colors and to deletevisual colors that are less dominant, resulting in a smaller (morerepresentative) set of visual colors, such as six colors, representing amood of each song.

In a similar manner, melody, rhythm and harmony may also be mapped tocolors. For example, sound without melody, harmony, or rhythm is knownas white noise. A song with lots of rhythm, harmony and melody may bethought of as being black. Sounds that have equal attributes of melody,rhythm and harmony, may therefore be thought of as being gray.Harmonious tones without melody or rhythm may be mapped to a specificcolor, such as yellow. Music that includes melody and harmony, but nodriving rhythm, may be considered green. Music with lots of melody, butlittle rhythm or harmony, may be considered cyan. A simple melody with ahard driving rhythm may be blue. Music with lots of rhythm, some melody,and some harmony, may be purple. Music with lots of rhythm and someharmony, but little melody, may be red. The above color association isjust an example and other color associations may readily be used. Thepoint is that combining this form of music colorization with the musicaltristimulus colorization technique may result in songs being identifiedwith more predictable color identifiers.

According to a research study published in the journal BMC MedicalResearch Methodology (Feb. 2, 2010), people on average tend to pickdifferent colors to describe different moods. FIG. 6 illustrates asimplified version of a color wheel based on that study. While the studywas more focused on the colors that people picked based on their moodsassociated with their health, i.e., healthy, anxious or depressed, manyother examples exist that associate colors with human moods that areunassociated with health per se, such as happy, sad, etc. FIG. 7illustrates one example of colors associated with moods.

Using any appropriate color/mood association chart, it is thus possibleto identify the mood(s) represented by a song for the color identifiersfor that song. The mood(s) identified for a song using the colortechnique can then be compared to the mood(s) identified for the samesong using audio fingerprints or other mood identifying techniques.There may be a correlation between the two, but now always, whichillustrates that at least one of the techniques may be less accurate,which is why at least one additional mood identification technique maybe helpful in order to triangulate the mood identifiers for a song. Forexample, it may be difficult to accurately identify the location of anobject based on two reference points (signals between a mobile deviceand two cell towers, for example), but when three reference points areused, the object's location can usually be fairly accurately identified,absent any signal interference, or the utilization of techniques foreliminating or accommodating for such interference. The same principlesmay be applied with moods. With two mood identifiers for a song, it maybe possible to identify the mood of the song, but that identificationmay not always be accurate. When a third mood identifier is added,however, the accuracy may increase significantly. Additional moodidentifiers may likewise be added to further increase accuracy, up to acertain point, where the addition of further mood identifiers makes nosignificant statistical difference.

A third mood identification technique for music includes shape. One typeof system that generates shapes associated with songs are softwareprograms known as “visualizers,” such as VSXU, MILKDROP, GFORCE andmultiple different plugins for APPLE's ITUNES. Such visualizers tend touse the same audio frequency data utilized to generate audiofingerprints, so the resulting images may be similarly useful in termsof identify moods. However, despite the fact that the same frequencydata may be used as an input to an audio fingerprint system and avisualizer system, some visualizers also use loudness as an input, whichmay cause the visualizer to identify different moods than the audiofingerprint system using the same frequency data, where amplitude maynot be used to generate the audio fingerprint. In addition, eachvisualizer may analyze the frequency data differently and may thereforeidentify different moods.

Since it is desirable to have a fairly high level of mood identificationcorrelation between the different systems used, it may be problematic ifthe visualizer identifies different moods than the other moodidentification systems. Accordingly, mood identification systems may bechosen based on the level of correlation between the moods each systemidentifies.

While a visualizer may be used as a mood identification system, somevisualizers are designed to create different visualizations for eachsong every time the program is run, so some visualizers may not be wellsuited for mood identification for this reason. In addition, somevisualizers produce very complex imagery associated with songs. Forexample, one of the simpler screenshots generated by the GFORCEvisualizer, and made available on the SoundSpectrum, Inc. website,http://www.soundspectrum.com/, is illustrated in black and white in FIG.8. The original image is a mixture of black, white and purple colors.Other images generated by the GFORCE visualizer are significantly morecomplicated.

Similarly complicated and unique shapes may be generated from songs inmuch the same way that images may be generated from fractals. Forexample, in HARLAN J. BROTHERS, INTERVALLIC SCALING IN THE BACH CELLOSUITES, Fractals 17:04, 537-545, Online publication date: 1 Dec. 2009,it was noted that the cello suites of Johann Sebastian Bach exhibitseveral types of power-law scaling, which can be considered fractal innature. Such fractals are based on melodic interval and its derivative,melodic moment, as well as a pitch-related analysis. One issue withcomplicated shapes representing moods, such as those images generated bythe GFORCE visualizer or a fractal based system, although they may beused for mood identification, is that the images may be too complicatedfor many users to reliably identify a mood based on the generatedimages.

Accordingly, the present disclosure describes a simpler type of imagerythat may be utilized to identify the moods in songs, and which may becombined with the color mood identification system described above. Thepresent disclosure uses audio fingerprints, instead of the frequencydata used to generate the audio fingerprints (although the frequencydata may be used instead of the fingerprint), to generate simplistic,three-dimensional geometric shapes for each song. By using thefingerprint itself, although analyzed in a different way, a correlationbetween the moods identified with the fingerprint and the shapes may beassured.

As previously, described, an audio fingerprint may be used to generate astatic visual representation of a song, but like visualizer images andfractal images, the visual representation may be too complicated forhumans to easily identify similarities between different fingerprints.By converting the audio fingerprint into a simple geometricrepresentation of the complex data, it is easier for humans to easilyrecognize and differentiate between the visually represented songs.FIGS. 9, 10 and 11 illustrate three different examples of shapesgenerated from audio fingerprints that identify the mood of a song. Theshapes are also colored in accordance with the mood that has beenidentified. Song 1 of FIG. 9 is visualized as a rather sharp angledsquare pyramid, colored bright red; the shape and color of which mayidentify a song with an aggressive mood. Song 2 of FIG. 10 is visualizedas a rather 90 degree angled parallelpiped, colored purple; the shapeand color of which may identify a song with a sad mood. Song 3 of FIG.11 is hexagonal three dimensional shape, colored green; the shape andcolor of which may identify a song with a neutral mood.

The details that make up the geometric shape (shape, angles, number ofsides, length of lines) are determined by the unique data containedwithin the audio fingerprints. Since each of the above songs aredistinctly different from one another, they generate distinctlydifferent shapes. Songs with more aggressive moods tend to generateshapes with sharper angles. Songs with sadder or more mellow moods tendto generate shapes with angles that are close to 90 degrees. Songs withmore ambiguous moods tend to generate shapes with more ambiguous shapes.

At the same time, there may also be degrees of similarities betweensongs that are based on the level of mood represented. For example, inFIG. 12A, Song A, which is 95% aggressive and bright red, may bedistinguishable from Song B of FIG. 12B, which is 70% aggressive butstill also bright red. Both songs may represent aggressive moods andhave similar shapes, but the more aggressive song may have longer linelengths. Alternatively, the song that includes more of the identifiedmood may have sharper angles. Other shapes may also be used to identifydifferent moods than the shapes shown herein. For example, twodimensional shapes may be used or other three dimensional shapes may beused, such as any homomorphic shape.

With reference back to FIGS. 12A and 12B, the difference in the twoshapes may be due to a variety of factors, such as the presence ofvocals, which may lend heavily to the aggressive mood identification.The percentage of mood represented above may represent how far a songleans towards a particular identification. Without the vocals, a songmay be less aggressive. As the aggressive percentage for songs islowered, the color of the mood may also begin to shift slightly awayfrom bright red to more of an orange-red color (i.e., as the percentagelowers, the color may shift hue more towards whatever mood wasappropriate). Also, while the square base of the geometric shapeillustrated in FIGS. 12A and 12B may be the same in both songs,different base shapes may also be used. As illustrated in FIGS. 12A and12B, the top and mid-level areas of the shape, representing the top andmid-range frequencies of the song, may change significantly.Nevertheless, based on the two shapes represented in FIGS. 12A and 12B,it may be possible to note that the two songs are similar and havesimilar moods without hearing either of the actual songs.

In view of the above, it may be possible to identify the mood or moodsin a particular song in at least three different ways, as illustrated inFIG. 13, by shape, fingerprint and color.

With these three different types of classifications, it may be possibleto identify in any type of music or other content correspondingcommonalties. The fingerprint, color and shape may define where a songor other type of content fits within any type of content selectionsystem, which may make it easier for any user of the selection system toselect content they desire.

An alternative to using audio fingerprints to objectively identify moodsin songs is to use rhythm, texture and pitch to objectively identifymoods in songs. And, as further described below, it may likewise bepossible to objectively determine scores for rhythm, texture and pitchfor purposes of using those scores to determine the moodclassification/mood class/mood for each song. FIG. 14 illustrates a setof RTP scores, organized by mood among a number of moods, that may beused to train a machine learning system, such as a multiclass SupportVector Machine (SVM) or other appropriate classifier. As illustrated,RTP is represented by a vector having only three attributes scored witha whole number integer between 1 and 5, although an alternative scoringsystem may be used. For example, vectors for one of the moods, Happy,are (3, 4, 4) and (3, 3, 5) and (3, 5, 5) and (3, 3, 4), indicating thatthe rhythm scores were all 3's, the texture scores ranged between 3 and5, and the pitch scores ranged between 4 and 5. Other moods trained inthis example include Excited, Manic, Cautious, Peaceful and Sad. Whileonly six moods were trained for this example fewer or more moods mayhave been used. When fewer moods are used, the functional margin (thelargest distance to the nearest training data point of any class) may belarger. Reasonable functional margins have been achieved with six moodsthat may not be as possible if the total number of moods is increased.

A SVM trained with the RTP scores for the moods listed in FIG. 14 wasthen used to classify a greater number of songs. As illustrated in FIG.15, the 65 songs listed therein were classified in the mood classes theywere expected to be classified in with one hundred percent (100%)success. While the vectors for the 65 songs do not represent thetotality of all possible RTP scores, the functional margin within mostof the moods was quite high, as indicated by SVM probability percentagesin the 70 to 90+ percentile range for all but 10 of the 65 songs, and 8of those 10 in the 60 percentile range. A classification system trainedin this manner may efficiently classify a large number of songs intospecified moods classes. Once in those mood classes, the songs may belistened to by a user or further customization may be performed togenerate specific groups of songs that the user wants to hear.

In an embodiment, as illustrated in FIG. 16, songs could be input by auser in a variety of ways for mood classification as noted above, eitherusing audio fingerprints or RTP scoring. For example, thecharacteristics of a digitized representation, such as the audiofingerprint, could be determined on an end user device, based on one ormore songs in a library or file stored on the end user device. Thecharacteristics may be limited to just those characteristics necessaryto objectively determine the RTP for the songs. Those necessarycharacteristics may then be sent from an end user device to anothercomputer, such as a server, that includes the analytical softwarenecessary to determine the moods of the songs from the necessarycharacteristics. This embodiment removes the need for the end userdevice to send copies of songs to the other computers, thereby avoidingany copyright issues that might result for generating or distributingsuch copies.

In an embodiment, the characteristics of the digital representation ofsongs may be analyzed to determine their moods as described above beforesongs are first published by artists or record labels representing theartists. Alternatively, the artists or recording labels could input thesongs for analysis, step 1602. If the moods of the songs are determinedbefore being published, the metadata for each song could include themood(s) for in the same manner as genre, artist, title, etc.

In the same manner songs may be input by a music services, step 1604,such as ITUNES, SPOTIFY, PANDORA and the like. Once input, the songs maybe analyzed to determine either the audio fingerprints or the RTPscores, step 1606, for the songs. Once the songs have been analyzed orscored, the songs may be placed into different mood classifications asnoted above, step 1608, and as appropriate for the analysis/score of thesongs. Once the moods of songs are determined, the music service couldthen include the mood of each song with the streamed data. In anembodiment, the music service analyzes the songs itself In the mannerdescribed above and provides mood information with the streamed songs sousers can select songs based on mood as well as other data.

In an embodiment, users may be able to customize moods after the moodshave been first determined, step 1612. As the moods of the songs areobjectively determined, but mood is inherently a subjectivedetermination of the listener, not every objective mood determinationwill fit a particular listener's subject mood. Hence, it may bedesirable to allow listeners to change moods or groups songs into theirown categories. If a listener/user does not want to customize any aspectof a mood for a song, then the user may be enabled to just listen to thesongs as classified, step 1614. Alternatively, the listener/user wantsto customize the moods or categorize the songs based on moods, they maydo so, step 1616. In an embodiment, the user may want to categorizesongs with the same mood or perhaps different moods within a singlecategory that they name themselves, such as “Sunday Listening,” whichincludes a grouping of songs with different moods that a user likes tolisten to on Sundays.

User preferences may include negative or positive preferences in a widevariety of categories. For example, a user could indicate a desire notto listen to any country music or pop songs within a particular mood, orto only listen to songs published after 1979. Preference may includegenre, artist, bands, years of publication, etc. Once a user hascustomized the mood classes based on their preferences in step 1616, theuser may then be enabled to listen to the music based on thecustomizations, step 1618. It should be noted, that just because one ormore songs were excluded from a particular mood class by acustomization, that does not change the mood class associated with thoseone or more songs. A user may create a customized play list of songs onone occasion based on particular preferences and then create a differentcustomized play list of songs based on other preferences on anotheroccasion. Thus, the songs remain classified as they are and remain inthe mood classes to which they are assigned regardless of the user'scustomizations, which apply only to the customized lists created in step1618.

As noted above, in addition to objectively analyzing or scoring songs inorder to classify them by mood, it may also be possible to objectivelyanalyze songs in order to generate RTP scores for the songs. Forexample, the chromagrams generated as part of the process of creatingaudio fingerprints may also be used to objectively determine the pitchfor songs for which chromagrams have been generated. The chromagram isanalogous to a helix that circles around from bottom to top like acorkscrew. The musical scale goes around the helix, repeating keys eachtime it goes around, but each time at a higher octave. Just as there are12 octaves in the scale, there are 12 vectors in the chromagram. If onewere to attempt to scale the 12 vectors of the chromagram for each songacross the 88 keys to a piano, for example, it may be very difficult todo, but that is not actually necessary.

The same SVM system described above can be used for purposes ofobjectively determining pitch in songs by determining a number ofcombinations of chromagram vectors among all possible combinations ofchromagram vectors that correspond to certain pitch scores and thentraining a multiclass SVM with that number of combinations of chromagramvectors. Once the SVM has been trained, the SVM may then be used todetermine which pitch score (such as an integer between 1 and 5)corresponds to every single possible combination of chromagram vectors,and once a set of all of the predetermined combinations of chromagramvectors have been mapped to different pitch scores, future pitch scoresmay then be determined by comparing a combination of chromagram vectorsagainst the set of predetermined combinations of chromagram vectors andassigning the pitch score to the music based on a match between thecombination of chromagram vectors to one of the predeterminedcombinations of chromagram vectors among the set of predeterminedcombinations of chromagram vectors.

Training the SVM as noted above and testing the SVM based on a 15 songsubset of the 65 songs for which chromagrams have been producedgenerated correct results and acceptable functional margins for twelveof the fifteen songs, compared to the human generated scores for pitch,which are noted after each song below:

-   -   angstbreaker 3,{3→0.786129}    -   animal collective        5,{5→0.659113,2→0.104746,4→0.0921675,3→0.0778412,1→0.0661322}    -   arvo part 2,{3→0.477773,2→0.427112}    -   dirty beaches 3,{3→0.916016}    -   gesaffelstein_2 1,{3→0.380862,4→0.377543,1→0.152978,2→0.0736804}    -   gesaffelstein 2,{2→0.688006,4→0.157389,5→0.0716296}    -   ghibli jazz 5,{3→0.517388,5→0.253165,2→0.120315,4→0.0659154}    -   have a nice life 2,{2→0.786667,1→0.0860961}    -   kap bambino 3,{3→0.82835}    -   lightning bolt 4,{4→0.784288}    -   michael nyman 3,{3→0.880959}    -   nujabes2 3,{3→0.769765,4→0.0944392,1→0.0901176}    -   nujabes 4,{4→0.5828,3→0.186997,1→0.115422,2→0.0681724}    -   perez prado 4,{4→0.599685,3→0.256931,2→0.0731682}    -   portishead 1,{1→0.573343,3→0.145585,2→0.113073,4→0.111257}        Additional fine tuning and training will likely yield better        results.

Texture generally relates to the singular or multiple melodies in a songand whether or not those melodies are accompanied by chords. Texture canalso be representative of the density of frequencies in a song overtime. In order to compute the chromagram used to generate the audiofingerprints and the objective pitch scores noted above, it is firstnecessary to generate the spectrogram for each song. The spectrogram isa visual representation of the spectrum of frequencies in each song asthe songs plays. As a result, the spectrogram for a song can be used torepresent the texture for a song. One manner of representing the textureand scaling the score from 1 to 5 is to average the frequency densitiesand separate those out by fifths. If the average frequency density for asong is in the first quintile, the texture score would be a 1 and if theaverage frequency density for a song is in the fifth quintile, thetexture score would be a 5.

Rhythm can also be denoted by a long list of complicated factors, butthe primary components of rhythm are Beats Per Minute (BPM) and timesignature. A number of currently available tools exist to measure BPM insongs as well as time signatures, which are an indication of how manybeats are contained in each bar and which note value is to be given onebeat. In a manner similar to that described above, the raw BPM and timesignature data generated by such tools can then be used to deriveaverages for both BPM and time signatures in the songs that may then bemapped to a 1-5 score. For example, a song with a consistently averageBPM throughout the song and neither too fast or too slow, along with aneven time signature, such as 4/4 time, may be scored a 3 for rhythm. Asong with a higher average BPM, but which is inconsistent in places, ora moderate average BPM, but either a changing time signature or othervariation, such as 5/4 time, may be scored a 4 for rhythm. Songs withslower BPMs and even time signatures may be scored a 2 for rhythm.

With regard to RTP scores and application of the SVM, once the SVM hasscored every possible combination of RTP scores there will be no need toclassify a song with the SVM once the song has been scored. For example,if a song has an RTP score of 3, 3, 5, its mood classification will beHappy because previously RTP scored songs with the same vector have beenclassified as Happy. Since every digital file, including any digitizedmusic file, has a computable MD5 hash associated with it, where the MD5hash is a cryptographic hash function producing a 128-bit (16-byte) hashvalue, typically expressed in text format as a 32 digit hexadecimalnumber, the MD5 hash can serve as a unique identifier for each song.Once a song has been scored, the MD5 hash can be computed and associatedwith the song. Thereafter, without rescoring a song, the MD5 hash canfirst be computed to see if the song has already been scored, and if so,the existing score can be used for that song, thereby greatlysimplifying the scoring process for known songs. If the song has notbeen scored, it will be scored and the MD5 hash will be associated withthat score. Other unique identifications associated with different typesof music formats may be used in a similar manner.

A block diagram of a music selection and organization system based onthe above disclosure is illustrated in FIG. 17. A memory 1702 stores aplurality of content. The data, such as frequency data, in that contentis then read and/or sampled by the sampler 1704 on a periodic basisuntil all of the content in the memory 1702 has been sampled, which maythen be updated from time to time with new content sampled by thesampler 1704 as the new content is added. After the content is readand/or sampled, usually on a piece by piece basis, the sampler, or adevice connected to the sampler, such as the analyzer 1706, generates astatic representation of the piece based on the sampled frequency data,which may be a static visual representation, such as a spectrogram. Thestatic visual representation may then be filtered by the filter 1708 tocapture intensity differences represented in the static visualrepresentation and to generate a filtered representation of the content.The analyzer 1706 may also be used by the filter 1708 to create thefiltered representation, such as a chromagram. An encoder 1710 may thenencode the filtered representation and create digitized representationsof the content based on the encoded filtered representation, such as anaudio fingerprint. The analyzer 1706 may also identify characteristicswithin the digitized representations that correspond to moods in thecontent and generate three-dimensional shapes that correspond to themoods. The analyzer 1706 may also analyze the data for other purposes,such as to determine the MD5 hash, analyze the spectrogram to determineaspects of rhythm and texture, and analyze the chromagram to determineaspects of pitch, all in order to determine RTP scores for moodclassification. The mood identifications corresponding to the content isthen fed to the user interface. Other data read from the input files,such as metadata (i.e., artist, title, year, genre and other data), mayalso be fed to the user interface. Users are then able to view thethree-dimensional shapes to select content based on the moodsrepresented by the three-dimensional shapes.

The three-dimensional shapes may be wire frames or solids. Eachthree-dimensional shape may include at least one angle and one side,where the degree of the angle and the length of the side identify apercentage of a mood identified in the content. The three-dimensionalshapes may also include one or more colors that represent moods in thecorresponding content. The color may be determined by creating a colorrepresentation of the content based on the frequency data sampled fromthe content. Predominant colors identified in the color representationsare kept and less predominant colors in the color representation aredeleted so as to generate one or more colors representing the mood(s) inthe content. The color representation may be based on tristimulusvalues. The color representation may also be based on combinations ofmelodies, harmonies and rhythms in the content and/or RTP data. Themoods may also be derived by the analyzer directly from the digitizedrepresentations. The content may be music or video that includes music.

In an embodiment, a user of the selection and organization system mayalso load a song or other content of their choice into the selection andorganization system so as to generate a color, shape, RTP score, orfingerprint representation, and then search for similarly identifiedcontent. Extending the same idea further from that, the user mayrandomly generate a visual representation without specific content inmind, and find content based on fingerprints, RTP scores, colors orshapes aesthetically pleasing to the user.

Conditional language used herein, such as, among others, “can,” “could,”“might,” “may,” “e.g.,” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain examples include, while otherexamples do not include, certain features, elements, and/or steps. Thus,such conditional language is not generally intended to imply thatfeatures, elements and/or steps are in any way required for one or moreexamples or that one or more examples necessarily include logic fordeciding, with or without author input or prompting, whether thesefeatures, elements and/or steps are included or are to be performed inany particular example. The terms “comprising,” “including,” “having,”and the like are synonymous and are used inclusively, in an open-endedfashion, and do not exclude additional elements, features, acts,operations, and so forth. Also, the term “or” is used in its inclusivesense (and not in its exclusive sense) so that when used, for example,to connect a list of elements, the term “or” means one, some, or all ofthe elements in the list.

In general, the various features and processes described above may beused independently of one another, or may be combined in different ways.All possible combinations and subcombinations are intended to fallwithin the scope of this disclosure. In addition, certain method orprocess blocks may be omitted in some implementations. The methods andprocesses described herein are also not limited to any particularsequence, and the blocks or states relating thereto can be performed inother sequences that are appropriate. For example, described blocks orstates may be performed in an order other than that specificallydisclosed, or multiple blocks or states may be combined in a singleblock or state. The example blocks or states may be performed in serial,in parallel, or in some other manner. Blocks or states may be added toor removed from the disclosed examples. The example systems andcomponents described herein may be configured differently thandescribed. For example, elements may be added to, removed from, orrearranged compared to the disclosed examples.

While certain example or illustrative examples have been described,these examples have been presented by way of example only, and are notintended to limit the scope of the subject matter disclosed herein.Indeed, the novel methods and systems described herein may be embodiedin a variety of other forms. The accompanying claims and theirequivalents are intended to cover such forms or modifications as wouldfall within the scope and spirit of certain of the subject matterdisclosed herein.

What is claimed:
 1. A method for identifying mood in content,comprising: generating a static visual representation of an item ofcontent based on frequency data sampled from the item of content;filtering the static visual representation to capture intensitydifferences at specific frequencies represented in the static visualrepresentation and generating a filtered representation of the item ofcontent; encoding the filtered representation to create a digitizedrepresentation of the item of content; identifying characteristicswithin the digitized representation that correspond to a rhythm (R), atexture (T), and a pitch (P) within the item of content; and determininga mood among a plurality of moods that correspond to the R, the T andthe P.
 2. The method of claim 1, wherein determining a mood includesobjectively determining a R-value corresponding to the R, a T-valuecorresponding to the T and a P-value corresponding to the P,collectively representing a RTP score.
 3. The method of claim 2, whereinthe RTP score is a RTP vector, and wherein determining includesidentifying a mood that corresponds to the RTP vector.
 4. The method ofclaim 2, wherein the RTP score is a RTP vector, further comprisingtraining a machine learning system based on the characteristics withinthe digitized representation that correspond to the RTP vector.
 5. Themethod of claim 4, further comprising identifying an unknown mood ofdifferent items of content by generating, filtering, encoding andidentifying the different items of content in accordance with claim 1,and determining the unknown mood with the trained machine learningsystem.
 6. The method of claim 4, further comprising identify unknownmoods for a plurality of different items of content by generating,filtering, encoding and identifying each of the plurality of differentitems of content in accordance with claim 1, and determining the unknownmoods of each of the plurality of different items of content with thetrained machine learning system.
 7. The method of claim 6, wherein theitem of content and different items of content are songs or includesongs.
 8. The method of claim 2, wherein the RTP score is a RTP vector,wherein the item of content is a song or includes a song, wherein theitem of content has a first unique identification that is associatedwith the mood of the item of content that corresponds to the RTP vector,further comprising: receiving a request to perform generating,filtering, encoding, identifying and determining for a second item ofcontent having a second unique identification that matches the firstunique identification; and based on the request, identifying the mood ofthe second item of content based on the RTP vector corresponding to thefirst unique identification.
 9. The method of claim 1, wherein thestatic visual representation is one or more of a spectrogram, achromagram or an audio fingerprint.
 10. A method for identifyingcharacteristics of a rhythm (R), a texture (T) and a pitch (P) for anitem of content, comprising: generating a static visual representationof the content based on frequency data sampled from the content;filtering the static visual representation to capture intensitydifferences at specific frequencies represented in the static visualrepresentation and generating a filtered representation of the content;encoding the filtered representation to create a digitizedrepresentation of the content; and identifying characteristics withinthe digitized representation that correspond to the R, the T and the Pfor the item of content.
 11. The method of claim 10, further comprising:sending the identifying characteristics from a first computer to asecond computer; and receiving from the second computer at the firstcomputer a determination of a mood that correspond to the R, the T andthe P for the item of content.
 12. The method of claim 11, wherein thedetermination is based on an objective determination of a R-valuecorresponding to the R, a T-value corresponding to the T and a P-valuecorresponding to the P, collectively representing a RTP score.
 13. Themethod of claim 12, wherein the RTP score is a RTP vector, and whereinthe determination is based on identifying a mood that corresponds to theRTP vector.
 14. The method of claim 11, wherein a R-value corresponds tothe R, a T-value corresponds to the T and a P-value corresponds to theP, collectively representing a RTP score, wherein the determination isbased on a comparison of the RTP score to a plurality of previouslydetermined RTP scores for a plurality of items of content.
 15. Themethod of claim 14, wherein the comparison is also based on a uniqueidentifier associated with the item of content on other uniqueidentifiers associated with each of the plurality of items of content.16. The method of claim 10, wherein the item of content is a song orincludes a song.
 17. The method of claim 10, further comprising:determining a mood that correspond to the R, the T and the P for theitem of content; and including the mood in metadata associated with theitem of content.
 18. The method of claim 16, wherein the item of contentis a song or includes a song.
 19. The method of claim 10, furthercomprising: determining a mood that correspond to the R, the T and the Pfor the item of content; and including the mood in streaming dataassociated with the item of content.
 20. The method of claim 19, whereinthe item of content is a song or includes a song.